There are several different types of footings for all types of construction.  Where you have low density soils or sub standard ground on which you have to lay your footings.  The type of footings you are laying depend not just on the ground but also the building or other, you intend to construct.  In some cases there are situations where you might need to implement what is called Bored Pilling.  

A “Board pile” is where a bore hole is sunk into the ground to the required depth, a steel rod cage, steel rods and or other rebar is then dropped into the hole then concrete is poured into the bore.  This then produces your bored foundation on which to build the base to construct upon.

This system is used in a lot of cases from bridge building, heavy construction load building, tower and skyscraper block builds and other heave load bearing footing construction.  Some of the variations of these systems include, spun pile and Reinforced Concrete Square Pile are precast concrete piles are the main systems.

Typically, it requires drilling into approximately 50 meters depth of soil depending on both ground solidity and load to be supported.   There is also the “Red” pile system of the key types used and the advantages of a red pile system us that it won't produce a lot of vibration and has the advantage of noise level reduction when compared to traditional piling systems.

Applications and systems

Typically, bored piles, or drilled shafts, are used for tall buildings or massive industrial complexes, which require foundations that can handle the load of thousands of tons or more, or most probably, in unstable or difficult soil densities.  The system of drilling bored pile is different from RC Square pile or spun pile, which is done using a driving method the piling machine to be used will be different too.  Bored piling works require a specialist bored piling contractor  in the place of using a general piling contractor.  Using a simple step-by-step method of how to drill the bored pile on the construction site.

Challenges of a Bored Pile System

Like most deep foundation systems, bored piles have their challenges in order to have them drilled out correctly and deeply.

By pointing out the fact that the drilling method will depend on the density and type so you must have a good ground subsurface and soil investigation report that helps to decipher which drilling technology will be needed to be implemented.  It is solely the piling contractor responsibility which is based upon his experience, to decide the correct drilling technology and minimize disturbance of the surrounding soil, noise issues or unstable grounds as well as the loads involved.

Cohesion-less soils like sands, gravels, silts, and under the water table or not, the hole must be supported using steel cages or stabilizing mud such as bentonite suspension. The bentonite is really a messy one and you might want to avoid that if there is another solution you could implement.  Once this process is completed,​ a reinforcement bar would be dropped into place and concrete would then be poured into the bore hole as detailed previously above.

Most bored Pile Advantages

Some of the main advantages of these bored pile or drilled shafts over your typical conventional footings or other types of piles include (but are not limited to):

• Piles of variable lengths can be extended through soft compressible or swelling soils, into suitable bearing material.

• Piles can be extended to depths below frost penetration, and seasonal moisture variation.

• Large excavations and subsequent backfill are minimized.

• Less disruption to adjacent soil.

• Absence of vibration will not disturb adjacent piles or structures.

• Extremely high capacity caissons can be obtained by expanding the base of the shaft up to three times the shaft diameter, thus eliminating construction of caps over multiple pile groups.

• For many design situations, bored piles offer higher capacities with potentially better economics than driven piles.

Bored piling is popular to be used in construction as a foundation, especially for bridge work and tall buildings as well. Bored piling work has to be done by specialist bored piling contractor, normal piling contractor cannot execute these type of work without experience and knowledge about bored piles.